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Nuclear Theory·nucl-th

Tuesday·December 27, 2022

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 06

    [Submitted on 23 Dec 2022] (cross-list from hep-lat)

    Unpolarized proton PDF at NNLO from lattice QCD with physical quark masses

    Xiang Gao🇺🇸 · Andrew D. Hanlon🇺🇸 · Jack Holligan🇺🇸 · Nikhil Karthik🇺🇸 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Sergey Syritsyn🇺🇸 · Yong Zhao🇺🇸

    We present a lattice QCD calculation of the unpolarized isovector quark parton distribution function (PDF) of the proton utilizing a perturbative matching at next-to-next-to-leading-order (NNLO). The calculations are carried out using a single ensemble of gauge configurations generated with highly-improved staggered quarks with physical masses and a lattice spacing of fm. We use one iteration of hypercubic smearing on these gauge configurations, and the resulting smeared configurations are then used for all aspects of the subsequent calculation. For the valence quarks, we use the Wilson-clover action with physical quark masses. We consider several methods for extracting information on the PDF. We first extract the lowest four Mellin moments using the leading-twist operator product expansion approximation. Then, we determine the dependence of the PDF through a deep neural network within the pseudo-PDF approach and additionally through the framework of large-momentum effective theory utilizing a hybrid renormalization scheme. This is the first application of the NNLO matching coefficients for the nucleon directly at the physical point.

    Comments:
    20 pages, 17 figures, and 3 tables; version accepted for publication in PRD
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2212.12569 [pdf]
    PRD(2023)·57 citations
  2. 07

    [Submitted on 24 Dec 2022] (cross-list from nucl-ex)

    Collective flow of light nuclei and hyper-nuclei in Au+Au collisions at = 3, 14.6, 19.6, 27, and 54.4 GeV using the STAR detector

    Rishabh Sharma🇮🇳

    Light nuclei and hyper-nuclei are produced in abundance in heavy-ion collisions. The production mechanism of these species in heavy-ion collisions still remains to be understood. In these proceedings, we report the transverse momentum and centrality dependence of elliptic flow () of , , and in Au+Au collisions at = 14.6, 19.6, 27, and 54.4 GeV. Mass number scaling of of light nuclei is shown. We also report the first observation of hyper-nuclei H and H directed flow () in = 3 GeV mid-central (5-40\%) Au+Au collisions in the fixed target mode.

    Comments:
    SQM 2022 proceedings
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2212.12679 [pdf]
    EPJ Web Conf.(2023)·2 citations
  3. 08

    [Submitted on 26 Dec 2022] (cross-list from nucl-ex)

    Unbound states in 17C and p-sd shell-model interactions

    Sunji Kim🇰🇷 · Jongwon Hwang🇰🇷 · Yoshiteru Satou🇰🇷 · Nigel A. Orr🇫🇷 · Takashi Nakamura🇯🇵 · Yosuke Kondo🇯🇵 · Julien Gibelin🇫🇷 · Nadia Lynda Achouri🇫🇷 · Thomas Aumann🇩🇪 · Hidetada Baba🇯🇵 · Franck Delaunay🇫🇷 · Pieter Doornenbal🇯🇵 and 33 other authors

    Unbound states in 17C were investigated via one-neutron removal from a 18C beam at an energy of 245 MeV/nucleon on a carbon target. The energy spectrum of 17C, above the single-neutron decay threshold, was reconstructed using invariant mass spectroscopy from the measured momenta of the 16C fragment and neutron, and was found to exhibit resonances at Er=0.52(2), 0.77(2), 1.36(1), 1.91(1), 2.22(3) and 3.20(1) MeV. The resonance at Er=0.77(2) MeV [Ex=1.51(3) MeV] was provisionally assigned as the second 5/2+ state. The two resonances at Er=1.91(1) and 3.20(1) MeV [Ex=2.65(2) and 3.94(2) MeV] were identified, through comparison of the energies, cross sections and momentum distributions with shell-model and eikonal reaction calculations, as p-shell hole states with spin-parities 1/2- and 3/2-, respectively. A detailed comparison was made with the results obtained using a range of shell-model interactions. The YSOX shell-model Hamiltonian, the cross-shell part of which is based on the monopole-based universal interaction, was found to provide a very good description of the present results and those for the neighbouring odd-A carbon isotopes - in particular for the negative parity cross-shell states.

    Comments:
    Physics Letters B 836 (2023) 137629, published
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2212.12997 [pdf]
    PLB(2023)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE